This question already has an answer here:
A little while ago I was playing two of my friends. One of my friends was playing a wolf/werewolf deck with Immerwolf and a few other creatures out on the battlefield. I was playing an enchantment deck and cast Path To Exile on the Immerwolf. Once the spell resolved my friend didn't remove the +1/+1 from his other creatures (from Immerwolf's ability).
I reasoned that since they weren't actual +1/+1 counters, they would no longer affect his creatures, since Immerwolf was in exile. He disagreed, saying that the +1/+1 would stay, whether or not Immerwolf was in play.
I didn't really feel like pushing the issue since it was just a kitchen table game and it also didn't really affect the outcome of the game. I'm just curious as to who was correct.